DOI QR코드

DOI QR Code

Numerical investigation of effects of rotating downdraft on tornado-like-vortex characteristics

  • Cao, Shuyang (State Key Lab of Disaster Reduction in Civil Engineering, Tongji University) ;
  • Wang, Mengen (College of Civil Engineering, Tongji University) ;
  • Zhu, Jinwei (Shanghai Urban Construction Design & Research Institute Shanghai) ;
  • Cao, Jinxin (State Key Lab of Disaster Reduction in Civil Engineering, Tongji University) ;
  • Tamura, Tetsuro (Tokyo Institute of Technology) ;
  • Yang, Qingshan (Chongqing University)
  • 투고 : 2017.10.18
  • 심사 : 2017.12.29
  • 발행 : 2018.03.25

초록

Appropriate modeling of a tornado-like vortex is a prerequisite when studying the near-ground wind characteristics of a tornado and tornado-induced wind loads on structures. Both Ward- and ISU-type tornado simulators employ guide vanes to induce angular momentum to converge flow in order to generate tornado-like vortices. But in the Ward-type simulator, the guide vanes are mounted near the ground while in the ISU-type they are located at a high position to allow vertical circulation of flow that creates a rotating downdraft to generate a tornado-like vortex. In this study, numerical simulations were performed to reproduce tornado-like vortices using both Ward-type and ISU-type tornado simulators, from which the effects of rotating downdraft on the vortex characteristics were clarified. Particular attention was devoted to the wander of tornado-like vortices, and their dependences on swirl ratio and fetch length were investigated. The present study showed that the dynamic vortex structure depends significantly on the vortex-generating mechanism, although the time-averaged structure remains similar. This feature should be taken into consideration when tornado-like-vortex simulators are utilized to investigate tornado-induced wind forces on structures.

키워드

과제정보

연구 과제 주관 기관 : National Natural Science Foundation of China (NSFC), Tongji University, Central Universities

참고문헌

  1. Cao, S. and Wang, J. (2013), "Statistical summary and case studies of strong wind damage in China", J. Disaster Res., 8(6), 1096-1102. https://doi.org/10.20965/jdr.2013.p1096
  2. Cao, S., Wang, J., Cao, J., Zhao, L. and Chen, X. (2015), "Experimental study of wind pressures acting on a cooling tower exposed to stationary tornado-like vortices", J. Wind Eng. Ind. Aerod., 145, 75-86. https://doi.org/10.1016/j.jweia.2015.06.004
  3. Chang, C.C. (1971), "Tornado wind effects on buildings and structures with laboratory simulation", Proceedings of the 3rd International Conference on Wind Effects on Buildings and Structures, Tokyo, Japan, 231-240.
  4. Church, C.R., Snow, J.T., Baker, G.L. and Agee, E.M. (1979), "Characteristics of tornado-like vortices as a function of swirl ratio: a laboratory investigation", J. Atmos. Sci., 36, 1755-1776. https://doi.org/10.1175/1520-0469(1979)036<1755:COTLVA>2.0.CO;2
  5. Haan, F.L., Balaramudu, V.K. and Sarkar, P.P. (2010), "Tornadoinduced wind loads on a low-rise building", Struct. Eng., 136, 106-116. https://doi.org/10.1061/(ASCE)ST.1943-541X.0000093
  6. Haan, F.L., Sarkar, P., and Gallus, W.A. (2008), "Design, construction and performance of a large tornado simulator for wind engineering applications", Eng. Struct., 30, 1146-1159. https://doi.org/10.1016/j.engstruct.2007.07.010
  7. Hu, H., Yang, Z., Sarkar, P. and Haan, F.L. (2011), "Characterization of the wind loads and flow fields around a gable-roof building model in tornado-like winds", Exp Fluids, 51(3), 835-851. https://doi.org/10.1007/s00348-011-1102-6
  8. Ishihara, T., Oh, S. andTokuyama, Y. (2011), "Numerical study on flow fields of tornado-like vortices using the les turbulence model", J. Wind Eng. Ind. Aerod., 99(4), 239-248. https://doi.org/10.1016/j.jweia.2011.01.014
  9. Kikitsu, H., Sarkar, P. and Haan, F.L. (2010), "Fundamental study on characteristics of tornado-induced wind load on low-rise building using a large tornado simulator", Proceedings of the 21th National Symposium on Wind Engineering, Tokyo, Japan, 149-154 (in Japanese).
  10. Kuai, L., Haan, F.L., Gallus, W.A. and Sarkar, P.P. (2008), "CFD simulations of the flow field of a laboratory simulated tornado for parameter sensitivity studies and comparison with field measurements", Wind Struct., 11(2), 75-96. https://doi.org/10.12989/was.2008.11.2.075
  11. Lewellen, D.C., Lewellen, W.S. and Sykes, R.I. (1997), "Largeeddy simulation of a tornado's interaction with the surface", J. Atmos. Sci., 54, 581-605. https://doi.org/10.1175/1520-0469(1997)054<0581:LESOAT>2.0.CO;2
  12. Liu, Z. and Ishihara, T. (2015), "Numerical study of turbulent flow fields and the similarity of tornado vortices using large-eddy simulations", J. Wind Eng. Ind. Aerod., 145(2015), 42-60 https://doi.org/10.1016/j.jweia.2015.05.008
  13. Liu, Z. and Ishihara, T. (2016), "Study of the effects of translation and roughness on tornado-like vortices by large-eddy simulations", J. Wind Eng. Ind. Aerod., 151, 1-24. https://doi.org/10.1016/j.jweia.2016.01.006
  14. Mitsuta, Y. and Monji, N. (1984), "Development of a laboratory simulator for small scale atmospheric vortices", J. Natural Disaster Sci., 6(1), 43-54.
  15. Monji, N. and Mitsuta, Y. (1985), "A laboratory experiment on the multiple structure in tornado-like vortices", Disaster Prevention Research Institute Annals, Kyoto University, No.26, B-1, 427-436 (in Japanese).
  16. Natarajan, D. and Hangan, H. (2012), "Large eddy simulations of translation and surface roughness effects on tornado-like vortices", J. Wind Eng. Ind. Aerod., 104-106, 577-584. https://doi.org/10.1016/j.jweia.2012.05.004
  17. Rotunno, R. (1977), "Numerical simulation of a laboratory vortex", J. Atmos. Sci., 34, 1942-1956. https://doi.org/10.1175/1520-0469(1977)034<1942:NSOALV>2.0.CO;2
  18. Sabareesh, G.R., Matsui, M. and Tamura, Y. (2013), "Characteristics of internal pressures and net local roof wind forces on a building exposed to a tornado-like vortex", J. Wind Eng. Ind. Aerod., 112, 52-57. https://doi.org/10.1016/j.jweia.2012.11.005
  19. Refan M. and Hangan H. (2017), "Surface pressures dependency on Reynolds number and swirl ratio in tornado vortices", Proceedings of the 13th Americas Conference on Wind Engineering, May 21-24, 2017, Gainesville, Florida, USA.
  20. Tamura, Y. (representative). (2007), "Report of investigation of serious tornado damage in Saroma-cho, Hokkaido", Grant-in-Aid for Scientific Research (in Japanese).
  21. Wang, J., Cao, S., Pang, W. and Cao, J. (2017), "Experimental study on effects of ground roughness on flow characteristics of tornado-like vortices", Bound.-Lay. Meteorol., 162(2), 319-339. https://doi.org/10.1007/s10546-016-0201-6
  22. Wang, J., Cao, S., Pang, W. and Cao, J. (2018), "Experimental study on tornado-induced wind pressures on a cubic building with openings", J. Struct. Eng. - ASCE, in press.
  23. Ward, N.B. (1972), "The exploration of certain features of tornado dynamics using a laboratory model", J. Atmos. Sci., 29, 1194-1204. https://doi.org/10.1175/1520-0469(1972)029<1194:TEOCFO>2.0.CO;2
  24. Zhang, W. and Sarkar, P., (2012), "Near-ground tornado-like vortex structure resolved by particle image velocimetry (PIV)", Exp. Fluids, 52, 479-493. https://doi.org/10.1007/s00348-011-1229-5

피인용 문헌

  1. POD-based analysis of time-resolved tornado-like vortices vol.33, pp.1, 2018, https://doi.org/10.12989/was.2021.33.1.013